Definition of synthesis parameters of ultrafine nickel powder by direct electrolysis for application in superalloy production

Development of the electrochemical synthesis method of ultrafine cobalt powder for a superalloy production

“…And higher temperatures decrease polarization of cobalt formation. These data correlate with data for nickel powder [30], however, at temperatures below 50 °С compact metal particles are observed in cobalt powder. This lowers the quality of cobalt powder for manufacturing of superalloys.…”

“…1) shows the limiting diffusion current density of 6 А/dm 2 . However, no such limiting current is observed in the preparation of nickel powder [30]. This can indicate a multi-stage process.…”

“…During the development of the electrochemical method for the synthesis of cobalt powder, the electrochemical parameters for the electrochemical synthesis of nickel powder [30] were used. Such choice was made because of similar properties of nickel and cobalt, and because the paper [30] describes the methodology for the synthesis of nickel powder for the production of superalloys.…”

“…A stainless steel cathode was placed into the cell. It was previously discovered [30] that during the synthesis of nickel powder, nickel anode behaves like a low-soluble electrode, it was decided to use two insoluble anodes. Nickel electrodes, plated with 3 μm of gold were used as insoluble anodes.…”

“…The development of the electrochemical method for cobalt powder synthesis was based on the already developed method for the electrochemical synthesis of nickel powder. The paper [30] describes the following electrolyte composition of nickel powder synthesis: Ni 2+ 0.1 mole/L, NH 4 + 1 mole/L, NH 3 •Н 2 О until рН 11. Because the chemical properties of cobalt are similar to nickel, the following ammonium-sulfate electrolyte was proposed: Со 2+ 0.1 mole/L, NH 4 + 1 mole/L.…”